For various well-known reasons, it is commonly necessary to use grounding electrodes to provide permanent electrical connections between metal structures and the earth. The most common type of grounding electrodes are grounding rods, typically 8 to 10 feet long, that are driven completely or almost completely into the earth. Electrical connections are made from the grounding rods to the structures being grounded, using suitable electrical conductors (e.g., grounding cables). Augered grounding rods are commonly used as alternatives to driven grounding rods.
An ideal grounding connection maintains zero voltage regardless of how much electrical current flows into or out of the earth. The quality of a grounding connection may be improved in a number of ways, by, for example:                increasing the surface area of grounding electrode coming into contact with the earth;        increasing the depth to which the grounding rod is driven or augered (in cases where the grounding electrode is a driven or augered grounding rod);        using multiple connected electrodes;        increasing the moisture content of the soil surrounding the electrode(s);        improving the conductive mineral content of the soil; and/or        increasing the earth surface area covered by the grounding system.        
To ensure that a sufficient electrical connection from the grounded structure to the earth is achieved, it is commonly required by government regulation and/or industry practice that the electrical resistance between an installed grounding electrode and the earth must be less than 25 ohms, and this typically must be confirmed by testing before the grounding electrode is put into service. The factors influencing the level of electrical resistance developed between a grounding electrode and the earth include soil type and moisture conditions, which can vary over time. Generally speaking, the presence of moisture in the soil will increase electrical conductivity between a grounding electrode and the earth will be greater, resulting in lower electrical resistance (as previously noted).
Driven grounding rods have proven to be effective if properly installed, but proper installation is not always easy or even possible in some types of terrain and soil conditions. For example, if a grounding rod hits a rock while it is being driven into the earth, “mushrooming” can occur at one or both ends of the relatively soft steel rod, due to the increased axial force acting on the rod a result of impacting the rock. It is also known for driven grounding rods to be bent due to hitting underground rocks such that their path through the earth is deflected significantly as the rod-driving process continues. It is even known in such circumstances for grounding rods to be bent and deflected so much that their lower ends emerge above the earth surface a few feet from the insertion point. These and other installation defects and deficiencies can result in excessive resistance begin developed by an installed grounding rod, which may necessitate installation of a second rod bonded to the defectively-installed rod and electrically bonded thereto, in order to result in a satisfactorily-low resistance value for the complete installation.
However, even when soil conditions are readily conducive to grounding rod installation, the presence of buried utilities (e.g., gas lines, electrical power lines, water lines) can give rise to the risk of personal injury and expensive utility repair costs should such buried utilities be contacted or penetrated by grounding rods during the rod installation process. These latter risks can be mitigated or avoided by the use of grounding mats that do not have earth-penetrating elements, but such devices may have less than desired or optimal functional effectiveness, and they typically are not suitable in situations where permanent grounding is required.
Another practical disadvantage of the conventional 8-to-10-foot grounding rod is that a ladder or other means is needed to access the upper end of the rod to initiate the process of driving the rod into the earth. This is a safety concern, as workers have been injured after falling from an unstable ladder or other temporary support means while trying to pound a grounding rod into the earth.